Mutations in SLC26A4 cause Pendred syndrome, an autosomal-recessive disorder characterized by sensorineural deafness and goiter, and DFNB4, a type of autosomal recessive nonsyndromic deafness in which, by definition, affected persons do not have thyromegaly.
All patients harbouring mutations in the SLC26A4 gene had goiter and a positive perchlorate discharge test: 3 were slightly hypothyroid and 2 euthyroid.
The PDS gene (7q31), responsible for Pendred syndrome (congenital sensorineural hearing loss and goiter), encodes a transmembrane protein known as pendrin.
The combination of all these symptoms suggested the diagnosis of Pendred syndrome (PDS), a disorder characterised by congenital sensorineural hearing loss and a variable degree of thyromegaly due to mutations in the SLC26A4/PDSgene.
Mutations of the PDS gene, encoding pendrin, are associated with protein mislocalization and loss of iodide efflux: implications for thyroid dysfunction in Pendred syndrome.
The present results question the sensitivity of the perchlorate test for the diagnosis of Pendred syndrome and support the use of a molecular analysis of the PDS gene in the assessment of individuals with severe to profound congenital hearing loss associated with inner ear morphological anomaly even in the absence of a thyroid goiter.
Phenocopies for deafness and goiter development in a large inbred Brazilian kindred with Pendred's syndrome associated with a novel mutation in the PDS gene.